JPS594584B2 - Electromagnetically operated directional control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes an electromagnetic actuating device, one spool disposed in a spool hole of a casing, an effective surface provided on the spool facing a return chamber, and an actuator penetrating the return chamber. directional control valve, the directional control valve having at least one switching rod operatively coupling the spool with the movable core of the electromagnet, and a device for damping the movement of the spool, in which case the spool has one supply chamber; , controls the connection with two consumption connection chambers located beside this supply chamber, and the connection between these two consumption connection chambers and one adjacent return chamber each, and the return chamber has a horizontal passage. These devices are connected to each other through a return portion and are connected to a return portion.

In the case of the known directional control valve of the above type having a three-chamber structure,
To avoid liquid shock in the pressure medium system.

Devices for damping spool movements are already known.

For this purpose, a damping piston is slidably guided on the switching rod, which, when the spool is deflected from the neutral position into the working position, is connected to the throttle of the sleeve fixedly arranged in the housing. He is forced to rush into the room.

The damping piston is loaded by a spring which is in addition to the return spring -q device.

The damping device is not only uneconomically constructed, but also damps the movement of the spool if the spool itself is brought close to a neutral position in which it cuts off its pressure medium connection.

A disadvantage of the known directional control valves is that when unloading the working chamber under pressure on the return, a force is created on the spool which accelerates the spool in the switching direction.

Such forces are caused by the dynamic pressure that builds up in the return chamber in the event of instantaneous high pressures and by the spool as a differential piston, leading to undesirable switching shocks.

The object of the invention is to improve the switching behavior of a directional control valve of the type mentioned at the outset with the simplest possible means.

According to the invention, this problem is solved in that a piston-shaped extension is connected to the spool in at least one return chamber, and this extension has a deflection surface on the side facing the consumption connection chamber, and the spool is in a position to unload the consumption-like connection chamber, the additional part with the deflection surface is located at least approximately in the region in which at least one of the openings of the return part or the transverse passage opening into the return chamber is located. By means of this simple measure, short accelerated switching movements of the spool and thus switching shocks are prevented when unloading the consumer connection chamber under high pressure. is achieved.

The switching of the directional control valve is therefore considerably softer and the switching noise is accordingly reduced.

The turbulence of the oil flow in the return chamber is reduced by the deflection surface.

This allows the cross section to be narrower for the same flow rate.

When using a return device, a particularly advantageous configuration is obtained if the extension is arranged between the piston-shaped spool section and the spring catch.

Even with this configuration, the impact force of the flow can be applied to the additional portion without being weakened.

This is because the interposed spring holder prevents the plate from weakening the flow.

The flow resistance is also advantageously created thereby.

Furthermore, it is advantageous if the extension or the spring support forms a stop associated with the plate.

This significantly increases the durability of the spool end face and the spring receiver against the plate.

This is because surface compression is reduced. The invention will now be explained with reference to the illustrated embodiment.

In FIG. 1, the casing 11 has a consistent spool hole 12
A directional control valve 10 is shown, which has a ring-shaped enlarged portion as many as the spool holes 1 and 2 mentioned above.

The central supply chamber 13 maintains pressure medium from a pressure medium source via passages (not shown).

There is one consumption connection chamber '1 on each side of the supply chamber 13.
4.15 is placed.

The consumption-like connection chamber 14.15 is connected to the consumption-like connection 16°1γ.

The outer enlargement forms a return chamber 18.19 which is connected to one another and to a return section 22 via a transverse channel 21.

The transverse channels 21 each form an opening 23 or 24 in the return chamber 18.19, which opening 23.24 is arranged as close as possible to the respective consumption connection chamber 14.15.

A corresponding arrangement applies to the opening 25 of the return part 23 which opens into the return chamber 18.

Each return chamber has a step 26, 2γ located at a small distance from the opening 23.24, the step 26.27
Via the return chamber 18,19 transitions into a larger diameter area.

Into the spool hole 12 a spool 28 is inserted longitudinally movably and gas-tightly, which in its central neutral position is divided into two spool sections 29, 31.
The consumption connection chamber 14.15 is isolated from the supply chamber 13 and the return chamber 18.19 by means of the connection chamber 14.15 and the consumption connection chamber 14.15 is selectively connected to the supply chamber or to the consumption connection chamber 14.15 in the working position. Connect to the return chamber.

Each spool section 29.31 transitions via a pin-shaped section 32.33 into a piston-shaped extension 34.35,
A switching rod 36.37 is connected to the extension 34.35.

Each extension 34, 35 has a conical deflection surface 38 on the side facing the consumer connection chamber 14, 15.

The outer diameter of the appendage 34,35 is only slightly smaller than the inner diameter of the spool hole 12 and the pin-shaped section 32
．． It is considerably larger than the outer diameter of 33.

The additions 34.35 each have one spring catch plate 42.4.
3, and the spring holder forms a stopper for 42 and 4.
3 forms, together with springs 44 and 45, a double-acting return device 46, which is known per se.

Said extensions 34, 35 are arranged on the spool 28 in such a way that in the working position shown in detail in FIG. 38, the deflection surface 38 directs the return flow to the opening 24.
The spool 28 is arranged to be deflected inward, thereby exerting an impact force on the spool 28.

The switching rods 36, 37 are operatively connected to one movable core of the electromagnets 4γ, 48 respectively.

The mode of operation of the directional control valve 10 is as follows.

In the neutral position of the spool 28 shown in FIG. 1, the consumption connection chamber 14.15 is blocked, while the return device 46td centers the spool 28 in the neutral position.

If the movable core of the electromagnet 48 pushes the spool 28 via the switching rod 37 towards the left into one working position, the spool section 29 opens the connection from the supply chamber 13 to the consumption connection chamber 14. do.

At the same time, the spool section 31 opens the connection from the consumption connection chamber 15 to the return chamber 19.

If the pressure in the consumption connection chamber 15 is relatively high before switching, the return chamber 19 will open if a momentary high pressure occurs.
For a short time there is a dynamic pressure within the spool 28 which acts on the effective end face of the spool 28 and accelerates it to the left during its switching movement.

This is because the instantaneous high pressure mentioned above acts with a time delay on the end face of the spool 28 located in the return chamber 18 on the opposite side from the return chamber 19 due to the horizontal passage 21 and the return section 22. .

However, by deflecting the return flow using the deflection surface 38, an impact force is exerted on the spool 28 which substantially cancels out the forces accelerating the switching movement already mentioned.

In this case, the return flow flows out through the transverse passage 21 without passing through either the spring receiving plate 43 or the spring 45.

In other words, the spring holder means that the blood does not create any additional resistance in the return flow.
Rather, since it is located outside the flow range of the return flow, the flow energy of the return flow acts on the deflection surface 38 without being weakened.

The switching of the directional control valve is significantly softer and the switching noise is considerably reduced due to the satisfactory compensation of the forces acting on the spool 28.

Depending on the position of the deflection surface 38 relative to the flow and return chamber 19, its size and its configuration, the switching of the directional valve is influenced over the majority of the travel of the spool 28.

Furthermore, the deflection surface 38 serves to reduce the turbulence of the return flow in the return chamber 19, so that the flow resistance is correspondingly reduced.

The extension 35 with the deflection surface 38 can be produced particularly simply by turning the spool 28 and at the same time can withstand long-term operation.

A stop 41 assigned to the return device 46 can be formed.

A similar soft switching is obtained if the movable core of electromagnet 4γ deflects spool 28 to its rightward working position.

Naturally, variations are possible without departing from the scope of the invention.

The spool may therefore have a positive or negative overramp.

The shape of the deflection surface 38 can also be changed.

Directional control valves with other configurations can be used as well.

For example, an addition with a deflection surface can be used in a two-position valve with only one neutral position and one switching position.

Furthermore, the invention is not limited to electrically actuated valves, but can also be advantageously used in the case of mechanical, pneumatic or hydraulic valves.

Naturally, it is not necessary for the hydraulic force components to be completely canceled out.

This is because a certain amount of residual force is often desired in order to obtain high switching capabilities.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, in which FIG. 1 is a longitudinal sectional view of a directional control valve and FIG. 2 is a sectional view of a portion of the directional control valve according to FIG. 1 with a spool in a working position. be. 10... Directional control valve, 11... Casing, 12.
... Spool hole, 13... Supply chamber, 14.15...
Consumption-like connection room, 16.17... Consumption-like connection part, 18.
19... Return chamber, 21... Side passage, 22... Return portion, 23° 24... Opening, 25... Opening, 26.2
7...Step part, 28...Spool, 29.31...
Spool section, 32, 33... pin-shaped section, 34.
35...Additional part, 36.37...Switching rod, 3
8... Deflection surface, 39° 41... Stopper, 42.4
3... Spring holder is a plate, 44° 45... Spring, 46...
・Returning device, 4γ, 48...electromagnet.

Claims (1)

[Claims] 1. An electromagnetic actuating device, one spool disposed in the spool hole of the casing, an effective surface provided on the spool facing the return chamber, and an electromagnetic actuator that penetrates the return chamber and connects the spool with the spool. A directional control valve having at least one switching rod in operative connection with a movable core of an electromagnet and a device for damping the movement of the spool, in which case the spool has a feed chamber and a feed chamber of the feed chamber. It controls the connection with two consumption-like connection chambers located nearby and the connection between these two consumption-like connection chambers and one adjacent return chamber,
In those versions in which the return chambers are connected to each other and to the return section via transverse channels, a piston-shaped extension 34,35 is connected to the spool 28 in at least one return chamber 18, 19. and this additional part 34, 35 has a deflection surface 38 on the side facing the consumption connection chamber 14.15, and the spool 28 is in a position to relieve the load of the consumption connection chamber 14.15. In addition, the extension 34.35 with the deflection surface 38 opens at least substantially into the return chamber 18.19.
A directional control valve characterized in that the opening of the directional control valve is located in a range in which at least one of 23, 24, and 25 is located. 2. It has a return device located within the return chamber. This return device was pressed by a spring to a step provided in the casing. Each spring holder, which acts as a stop for the spool when the spool is in its neutral position, has a disk, the extension 34,35 being a piston-like spool section 2.
2. A directional control valve according to claim 1, wherein the spring receiver is arranged between the 9° 31 and the plate 42, 43. 3. Directional control valve according to claim 2, wherein the extensions 34, 35 form stops 39, 41 belonging to the spring plates 42, 43. 4. The directional control valve according to claim 1, wherein the outer diameter of the additional portion (34, 35) is smaller than the inner diameter of the spool hole (12) and is at least approximately equal to the outer diameter of the spool. 5. The directional control valve according to claim 1, wherein the deflection surface 38 is formed in a conical shape. 6. The outer diameter of the pin-shaped section 32.33 is the same as that of the additional portion 34.
The directional control valve according to claim 1, which is designed to be considerably smaller than the outer diameter of 35.